std-dc-newline-in-handler

Arguments:
stream character

Returns the character argument, after
side-effecting the stream specified by stream.
If reading, the charpos (stream-line-column) slot is set to 0,
otherwise the charpos (stream-line-column) slot is set to -1, to
anticipate the charpos increment that is performed by the character
reading strategy.

This function is an element of certain control tables for stream
input/output. Programs do not typically call it directly.